Untreated illness and outcome of psychosis.

Background: There has been controversy as to whether early intervention in psychosis can improve the outcome of the disorder.

Aims: To establish if there is an association between duration of untreated psychosis and the 4-year outcome of persons with a first episode of psychosis.

Method: Prospective naturalistic follow-up study of the outcome of consecutive first presentations with DSM-IV psychosis attending a community-based psychiatric service.

Results: A longer duration of untreated psychosis was associated with a significantly poorer functional and symptomatic outcome 4 years later. For schizophrenia and schizophreniform disorder, each increment in duration of untreated psychosis was associated with a 7.8 point decrease in global functioning and an increase in positive symptoms scores by 1.9 points.

Conclusions: This study extends the findings of short-term follow-up studies by confirming an association between duration of untreated psychosis and 'mid-term' outcome.